I was looking in the wardrobe of unearned skins I have and found one called 'Ice', The Subeta wiki says it's from a snowman-building event from 2015, Is it still possible to get it??

[-Winks] no, its not possible to get it currently. However staff are always looking at ways to re-release stuff, so I wouldn't say it will never be available. Just don't count on it happening soon.

Maybe a couple of months before Morostide next year, post a suggestion to add it the zapper line up?

I wish! I see so many things (and achievements) that have been retired that I want back. Like others have said, staff does sometimes re-release items, but I haven't ever seen an achievement be re-released :(

while achievements don't get re-released, the prizes sometimes do.

Good point - I'm glad you brought that up - I get so focused on achievements sometimes I forget ;)